The present invention relates to an apparatus for making braided, bound or piped openings in cloth workpieces, and more particularly to an apparatus for cutting and then turning or reversing the opening.
Federal Republic of Germany patent 878,299 (corresponding to U.S. Pat. No. 2,573,359) discloses a machine for the manufacture of edged buttonholes in which turning fingers having rib-shaped projections are developed on supports for corner knives. This document and all other prior art documents mentioned herein are expressly incorporated by reference. In order to effect corner cuts and turning, the corner knives, with turning fingers, are passed through the slit which has already been produced in the piece of cloth. The corner cuts are first produced. Upon further movement of the supports, the turning fingers are passed through the slit, turning over the piece of cloth upon their rearward movement.
In accordance with the German patent, the supports for the corner knives and the turning fingers are slidable in horizontal direction individually and/or together in a carriage which is mounted for displacement in vertical direction in a fixed support. A piston-cylinder drive initiates an operating movement of the carriage via a lever, from which movement a drive for the supports is tapped off by a pin/curved-groove mechanism. To this extent, movements of the supports in those directions, which are associated with each other in a fixed manner, are produced.
By producing the movement described, the movement of the supports always takes place at right angles to the piece of cloth but, with increasing penetration into the slit, also increasingly in the direction towards the corner cuts. In this way, the turning fingers extend far into the previously produced corner cuts, the rib-shaped projections even extending beyond the end points of the corner cuts. This can result in distorting the clamped pieces of cloth or, in the case of material of sensitive quality, even damaging the end points of the corner cuts. On the other hand, the function of such turning fingers requires that the edges of the cloth to be turned be dependably caught on the edges or projections of the turning fingers.
A similar machine is disclosed in U.S. Pat. No. 2,529,072.
The above devices can be used only to a limited extent in view of the described difficulties.
British patent 750,764 discloses a device for turning braided openings in articles of clothing including a turning tool which consists of several metal plates. With this device, barb-like edges of the plates positively engage the edges of the cloth workpiece to be turned, upon the pulling back of the turning tool, and grip the piece of cloth to be turned. The length of the turning tool corresponds to the length of the braided opening.
As compared with the first-mentioned device, this device has the disadvantage that suitable turning tools must be used for different lengths of openings. On the other hand, the first-mentioned device operates only in the region of the corner cuts, and can be adapted with respect to different lengths of openings.